Behaviour of short columns subjected to cyclic shear displacements: Experimental results

In this paper we present the results of an experimental program on eight reinforced concrete columns subjected to constant axial load and reversed statically imposed displacements. The loading conditions simulated those of a doubly fixed column. The parameters tested were: (a) the shear ratio αs=M/Vhαs=M/Vh (αs=1αs=1, 2 and 3), (b) the amount of the longitudinal reinforcement (ρs=0.02ρs=0.02, 0.04), (c) the amount of the transverse reinforcement (ρw=0.012ρw=0.012, 0.019), (d) the axial load ratio (ν=0.3ν=0.3, 0.6), and (e) two different main reinforcement layouts (conventional and a combination of conventional and bi-diagonal reinforcement). One of the major objectives of the tests was to measure the strains of the reinforcement (longitudinal and transverse) and of the concrete along inclined force-paths. Conclusions are drawn regarding the seismic design of columns with low shear ratios.